Traveling wave electron devices include examples such as backward wave oscillators and traveling wave tube amplifiers. While traveling wave electron devices have been used successfully in the microwave region (e.g., 3 GHz to 300 GHz), devices operating at frequencies above about 100 GHz have been difficult to obtain. As the frequency of operation goes up, many dimensions of the device must be reduced. Results obtained from simple scaling of device dimensions are generally poor, as the performance of scaled devices drops rapidly as frequency is increased. Moreover, numerous fabrication challenges are presented as frequency is increased. Accordingly, traveling wave electron devices have not generally been considered a viable solution for generating or amplifying radiation in the THz range.